The substrates required for the preparation of the following alcohol are

The correct answer is Option (4) → 

Correct answer:  CH₃–CH₂–CH₂MgBr and acetophenone (C₆H₅–CO–CH₃)

Reason:
The given product is a tertiary alcohol with three groups attached to the carbon bearing –OH:

• Phenyl group (C₆H₅–)

• Methyl group (–CH₃)

• n-Propyl group (–CH₂CH₂CH₃)

In Grignard reactions, a tertiary alcohol is obtained by adding an alkyl Grignard reagent to a ketone.

Here:

• Acetophenone (C₆H₅–CO–CH₃) already provides the phenyl and methyl groups

• Addition of n-propyl magnesium bromide (CH₃–CH₂–CH₂MgBr) introduces the propyl group

After hydrolysis, the required alcohol is formed.